Our transcription: But rocks forming the outermost layer of Earth today are much different in composition from that of many meteorites. For example, a common continental rock is granite, which is lighter in weight than meteoritic material. This suggests that this planet must have originally had a very different structure than it has today. Scientists believe that initially it was a homogeneous blob of silicon compounds, iron, magnesium oxides, and lesser amounts of all the other natural chemical elements.